In electric fuses for elevated circuit voltages it is often necessary to wind the fusible element, or elements, helically around a supporting structure of electric insulating material. Such insulating structures may take various forms, e.g. that of an extruded mandrel. In recent times it has often been found more desirable to fabricate supports for helically wound fusible elements out of plates of insulating material rather than to resort to extruded or similarly formed mandrels. Typical structures of this description are shown in U.S. Pat. No. 3,680,019 to F. J. Kozacka, 7/25/72, for HIGH-VOLTAGE FUSE HAVING A PLURALITY OF FUSE LINKS WOUND HELICALLY AROUND AN INSULATING MANDREL, in U.S. Pat. No. 3,846,728 to E. Salzer, 11/5/74, for HIGH-VOLTAGE FUSE INCLUDING INSULATING MANDREL FOR SUPPORTING FUSIBLE ELEMENTS, and in U.S. Pat. No. 3,851,289 to F. J. Kozacka, 11/26/74, for HIGH-VOLTAGE FUSE HAVING HELICALLY WOUND FUSIBLE ELEMENTS AND SUPPORT FOR HELICALLY WOUND FUSIBLE ELEMENT, all these patents being assigned to the same assignee as the present invention.
The above referred-to prior art relates to fuses wherein the helically wound fusible element extends between a pair of plug terminals.
The present invention relates to fuses wherein the helically wound fusible element extends between a pair of ferrules, or terminal caps, rather than between a pair of plug terminals.